Electric lamp



W. DAWSON ELECTRIC LAMP Se t. 17', 1929.

Original Filed May 23, 1927 Patented Sept. 17, 1929 UNITED STATES WILFRED DAWSON, OF LONDON, ENGLAND ELECTRIC LAMP Original application filed May 23, 1927, Serial No. 193,586. Divided and this application filed February' I 27, 1928, Serial No. 257,425, and in Great Britain May 31, 1926.

This invention relates to electric lamps of the multiple filament type and has for its main object to provide caps provided with improved means whereby the different filaments may be selectively brought into circuit while retaining the standard forms of lamp holder.

Other objects are, generally, to provide convenient means for selectively bringing difierent filaments into circuit, such means being associated with a tubular portion below the lamp cap proper as hereinafter described; further to provide the new or improved combinations and arrangements of parts embodied in the example now to be described and pointed out in the claims.

In. the accompanying drawings which illustrate the invention,

Fig. 1 represents in elevation the upper or cap portion of a three filament lamp in ac cordance with the invention.

Fig. 2 is a sectional plan corresponding to Fig. 1.

Fig. 3 is a perspective view of the screw for adjusting the tongues.

Referring to the drawings the sleeve or tubular portion B is not capable of rotary movement in relation to the upper sleeve A. A leading-in Wire d common to all the filaments or portions of the filament passes direct to the contact 0 and from the contact I) a wire D passes to an arcuate contact member F screwed to a circular or arcuate block E. This contact member has a portion G which is parallel to the sleeve B and between the sleeve and this contact member project spring tongues K, L, M, which project from the insulated block E and are connected to the leading-in wires e, f, g. The sleeve B is provided with holes P, Q, R, in any one of which a screw S can be engaged and deflect the corresponding tongue until it engages the portion G of the contact member F.

To prevent the screw from becoming live it must be insulated from the tongues and this can be done by providing an insulated point S for the screw or in any other suitable manner.

This application is a division of my application filed May 23, 1927, Serial No. 193,586.

It is to be understood that the invention is not restricted to the exact details shown and described but embraces such modifications as come within the ambit'of the accompanying claims.

I claim 1. An electric lamp of the multiple filament type having a cap, a bulb, a tubular por tion between said cap and said bulb and provided with a series of holes, cap contacts in connection with said cap, a common leadingin wire, other leading-in wires, an arcuate contact member within said tubular portion and connected to said common leading-in wire, selective contacts connected to the other leading-in wires, anda plug adapted to be inserted through one of said holes selectively to bring any one of said selective contacts into engagement with said arcuate contact mem- 2. An electric lamp of the multiple filament type comprising a cap and an extension thereof provided with a series of holes, an arcuate contact member, selective contacts of spring form bendable to engage the arcuate member, and a member adapted to be inserted 7 in any one of said holes selectively to bend one of said selective contacts.

In testimony whereof I aflix my signature.

WILFRED DAWSON. 

